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Standard dead length Crawford collets

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Peter F03/05/2019 22:14:52
98 forum posts
23 photos

I've been searching for some collets for my Portmac miller, Lathes.co describes them as 'standard dead length 1.5" crawford collets' that range in size from 1/8 to 1/2,

I've not managed to find any from this description, am I searching the wrong thing? are these style given an 'F' designation of some description that I need to search, any help much appreciated.

Michael Gilligan03/05/2019 23:35:10
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13559 forum posts
586 photos

Peter,

Have a browse through this album: **LINK**

https://www.model-engineer.co.uk/albums/member_album.asp?a=39260

MichaelG.

Martin Connelly04/05/2019 13:01:11
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847 forum posts
99 photos

Sorry about the scribbling on some pages. I didn't know at the time that it was going to be a useful historic document.

Martin C

Michael Gilligan04/05/2019 14:21:23
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13559 forum posts
586 photos

I didn't know it was your scribbling, Martin surprise

... I had assumed it was defaced by the apocryphal "previous owner" angel

MichaelG.

Martin Connelly04/05/2019 15:15:18
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847 forum posts
99 photos

I think I gave a copy to Tony at lathes.co.uk Thought it would go well with his archives. That may be how you got a copy. I downloaded it and printed it off years ago but have not found it online since then.

Martin C

Michael Gilligan04/05/2019 15:22:57
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13559 forum posts
586 photos
Posted by Martin Connelly on 04/05/2019 15:15:18:

I think I gave a copy to Tony at lathes.co.uk Thought it would go well with his archives. That may be how you got a copy. I downloaded it and printed it off years ago but have not found it online since then.

Martin C

.

No Martin, I got it directly from you [as PDF, if I recall correctly] and I converted it to jpg for this forum.

You are duly credited at the bottom of my album page.

I'm sure you can find our original conversation if you look.

MichaelG.

.

Your eMail 16/12/2015 at 08:06

Edited By Michael Gilligan on 04/05/2019 15:27:08

Martin Connelly04/05/2019 15:27:37
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847 forum posts
99 photos

I have obviously forgotten about it, I'll put it down to age and time passing.

Martin C

Michael Gilligan04/05/2019 15:33:42
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13559 forum posts
586 photos

**LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=112438

angel

Peter F04/05/2019 22:56:21
98 forum posts
23 photos

Hi, thanks for the replies, but unfortunately I can't find anything on there that matches the description on lathes.co

Michael Gilligan05/05/2019 07:21:40
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13559 forum posts
586 photos

Peter,

Try this catalogue: **LINK**

http://www.rotagriponline.com/datasheets/5C.pdf

.. ignore the 5C file-name !

MichaelG.

Peter F05/05/2019 15:15:44
98 forum posts
23 photos
Posted by Michael Gilligan on 05/05/2019 07:21:40:

Peter,

Try this catalogue: **LINK**

http://www.rotagriponline.com/datasheets/5C.pdf

.. ignore the 5C file-name !

MichaelG.

Thanks again, I did actually come across that in my search before, they all seem to be larger than what the machine needs, I was speaking to Tony at Lathes.co a few weeks ago about this mill, I said I'd send him some photos of the machine when it's restored for his site, so I messaged him today to see if he can put any light on the collet situation.

Peter F05/05/2019 23:48:39
98 forum posts
23 photos

I received a msg back from Tony, he said if you find any, buy them all and trade duplicate sizes with others etc, others? I think I've only seen 2 others for sale, ever, which basically makes me think hen's teeth.

However, had a rummage through some collets I have, found some Schaublin F16 collets that appear almost identical in some aspects, they are a 15 degree taper, from the links you provided for Crawford, their dead length collets also use a 15 degree taper, the part that protrudes through the collar is the same size, the widest part of the taper is the same, I've tried checking the original collet, but it impossible to tell with 100% certainty using my protractor.

Down side, the collets are a bit too long, not much, might only need shortening 3/4 mm

You'll see on the photos, the polished back end on the Schaublin collet is slightly too wide to fit in the bore, but again not much, I measured the top of the bore inside the spindle, and it's 15.6mm, the Back end of the Schaublin collet is the thickest part at 16mm,

what I'm thinking, shorten the Schaublin collets about 4mm, while the machine is stripped down, take a small amount off the inside of the spindle bore, the original collet never went this far up anyway,

What the general consensus on the the original being a 15 degree taper, does anyone know if Crawford would have used this on a 1950ish British machine?

Original on the left,

img_20190505_230250.jpg

img_20190505_230302.jpg

Below, the original collet in the Collar.

img_20190505_230455.jpg

Below the Schaublin F16 collet in the Collar

img_20190505_230536.jpg

Below the 2 collets.

img_20190505_230653.jpg

Michael Gilligan06/05/2019 06:05:49
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13559 forum posts
586 photos
Posted by Peter F on 05/05/2019 23:48:39:

I received a msg back from Tony, he said if you find any, buy them all and trade duplicate sizes with others etc, others? I think I've only seen 2 others for sale, ever, which basically makes me think hen's teeth.

.

Ahh ... That sort of 'Standard' devil

Thanks for posting the follow-up ... and good luck

MichaelG.

Michael Gilligan06/05/2019 06:26:12
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13559 forum posts
586 photos
Posted by Peter F on 05/05/2019 23:48:39:

What the general consensus on the the original being a 15 degree taper, does anyone know if Crawford would have used this on a 1950ish British machine?

.

Crawford was a Collet maker ... so would have made 'anything and everything'

Bespoke items for one machine were 'adopted' by others, and some became de facto 'standards'

You probably need to find what other machines used this 'standard' ... and then search old catalogues to confirm the design dimensions.

MichaelG.

Edited By Michael Gilligan on 06/05/2019 06:35:37

Peter F06/05/2019 23:11:39
98 forum posts
23 photos
Posted by Michael Gilligan on 06/05/2019 06:26:12:
Posted by Peter F on 05/05/2019 23:48:39:

What the general consensus on the the original being a 15 degree taper, does anyone know if Crawford would have used this on a 1950ish British machine?

.

Crawford was a Collet maker ... so would have made 'anything and everything'

Bespoke items for one machine were 'adopted' by others, and some became de facto 'standards'

You probably need to find what other machines used this 'standard' ... and then search old catalogues to confirm the design dimensions.

MichaelG.

Edited By Michael Gilligan on 06/05/2019 06:35:37

Having a think, I'd rather not alter the machine itself as this was more about restoring a rare old machine designed by a model engineer, than creating a machine I need to use.

so I've thought if I shorten the schaublin collets say 4mm, I can hold the collet in the lathe somehow, and turning very very slowly, use an ezelap credit card periodically press on the polished thicker end of the collet, to lap it so it will fit, I only need to take off 0.2mm to bring it down to the same OD as the original Crawford collet, and it's only the shiny part, the black part on the schaublin collet is smaller OD than the Crawford.

I used this method to deburr a B16 drill spindle with good results.

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